FIG. 1 depicts the overall architecture of an IGRS AV (Intelligent Grouping and Resource Sharing, Audio/Video profile) system, in which 3 logical units are defined, namely the media server 110, the media client 120 and the controller 130. The media server 110 is where content is located and managed, the media client 120 is where content is played and can be either a media player or a media recorder, while the controller 130 is the coordination unit between the media server 110 and the media client 120, and said controller can determine the interaction process of an audio/video application between the media server 110 and the media client 120. In the IGRS AV system, general device/service discovery, service invocation are governed by an IGRS core protocol, while AV specific control (such as multimedia content playback session setup and control) is governed by an IGRS AV protocol, and actual stream transport between the media server 110 and the media client 120 is fully out of band. For the stream transport control, there are two mechanisms: SOAP (Simple Object Access Protocol) based transport control and BCM (Back-Channel Message) based transport control. If the two stream transport control mechanisms are both supported in the media server 110 and the media client 120, a problem that needs to be solved relates to how either one of them is chosen to be operative.